The present invention relates to a radio selective call receiver such as a pager and, more particularly, to one with a circuit for preventing data loss when replacing a battery.
The conventional radio selective call receiver of the above type is designed to allow for appropriate battery replacement in order to prevent suspension of reception operation as well as making full use of the battery. For example, JP-A110495/1993 relates to a receiver comprising low voltage detection means for detecting the battery voltage decline below a predetermined reference voltage, alarm means for providing a first alarm in response to a low voltage detection signal sent from the low voltage detection means and low voltage elapsed time display means for displaying the time elapsed from the first alarm to the present time so that the battery can be replaced at an appropriate time.
The above-described conventional radio selective call receiver displays the time elapsed from the first alarm indicating a low voltage condition to the present time on its display unit, calling for a user carrying the receiver (hereinafter referred to as a user) to replace the battery upon seeing the displayed elapsed time and gives a second alarm to notify the user if the battery has not been replaced yet after a predetermined time has passed. From the displayed elapsed time after the first alarm however, the user is not able to obtain information as to how much of the capacity of the battery is left to retain the data stored in a memory of the second receiver. As the alarm operation is likely to consume more power of the battery compared with the LCD display operation, the second alarm decreases the effective service life of the battery in use.